In a typical cataract surgery, the capsular bag that is holding the crystalline lens of the eye is compromised, and the lens is then removed. A prosthetic Intraocular Lens (IOL) is then inserted into the capsular bag. To make this exchange, a hole (i.e. a capsulorhexis, or so-called “Rhexis”) is created on the anterior surface of the capsular bag. The objective of all of this is that the implanted prosthetic IOL will function in the stead of the removed cataractous lens. For this to happen, the optical axis of the prosthetic IOL (hereinafter the “IOL axis”) needs to be properly aligned with a defined axis of the eye.
It is well known that, after the removal of the cataractous lens, the capsular bag will shrink during the weeks immediately following surgery. From a surgical perspective, this reality poses several different possibilities. For one, capsular bag shrinkage may cause the IOL axis of the prosthetic IOL to become somehow misaligned. Such a misalignment can happen for various reasons, and it must necessarily be avoided. On the other hand, the fact there will be capsular bag shrinkage can be helpful, if the shrinkage is controlled to establish a proper alignment.
One way to control the postoperative capsular bag is to influence its shrinkage pattern. In particular, it is known that selectively weakening tissues of the capsular bag can be useful for this purpose. It is also well known that ocular tissues can be weakened by performing Laser Induced Optical Breakdown (LIOB) techniques. Before doing this, however, it is necessary to determine the nature and the extent of the required shrinkage control. In the context of postoperative cataract surgery, this requires an evaluation of the condition of the capsular bag, along with a determination of the orientation of the IOL axis of the implanted prosthetic IOL. The effect of capsular bag shrinkage can then be reasonably predicted.
In light of the above, it is an object of the present invention to provide a system and method for performing LIOB on tissue of a capsular bag in order to influence shrinkage of the bag after cataract surgery. Specifically, this is done for the purpose of properly orienting a prosthetic IOL on a defined axis of the eye, while the prosthetic IOL is positioned in the capsular bag. Another object of the present invention is to surgically influence capsular bag shrinkage in response to optical images of a prosthetic IOL in the capsular bag. Yet another object of the present invention is to provide a system and method for postoperatively aligning the IOL axis of a prosthetic IOL with a defined axis of an eye, by influencing the shrinkage of the eye's capsular bag. Still another object of the present invention is to provide a system and method for the postoperative alignment of an IOL which is simple to use, is easy to implement, and is relatively cost effective.